Beyond BMI : The Impact of the New Lancet Commission Diagnostic Criteria on Prevalence of Obesity in the United States

OBJECTIVE: This study compared population characteristics and overall US prevalence of obesity over time using the BMI criteria and the 2025 Lancet Commission criteria (i.e., the Excess Adiposity criteria). METHODS: We analyzed data from 58,053 adults aged ≥ 20 years in the National Health and Nutrition Examination Survey from 1999 to 2023. The Excess Adiposity criteria incorporated BMI, waist circumference, waist to hip and waist to height ratios, and body fat percentage to identify obesity, which was subclassified as preclinical or clinical based on organ dysfunction and activity limitations. Survey-weighted estimates were calculated to produce nationally representative trends. RESULTS: By BMI criteria, obesity prevalence increased from 31% (58.8 million) in 1999-2004 to 43% (101.3 million) in 2021-2023. By Excess Adiposity criteria, prevalence was higher and increasing from 51% (94.7 million) to 61% (143.9 million). The prevalence of clinical obesity is high due to a large number of people meeting criteria for organ dysfunction and/or activity limitations. CONCLUSIONS: Using the Excess Adiposity criteria to define obesity classifies nearly three in five US adults as having obesity, revealing substantial clinical, public health, and policy implications. The new criteria improve identification of individuals at risk but will require further strategies to achieve equitable, effective, and sustainable obesity prevention and treatment.